When American consumers shop for leather goods, it probably doesn’t enter their minds that their new belts, bags or shoes could be made not from cows or pigs but from cats and dogs. But not only is it a possibility, it’s hard for consumers to know what they have been sold.

Almost all that dog or cat leather comes from China. Now changes in Chinese culture, more pressure from the US and an upcoming trade agreement are combining to undermine this contraband trade.

The US banned the importation of dog and cat fur and skin, which is punishable by fines up to $10,000, as part of the Dog and Cat Protection Act of 2000. But distinguishing dog and cat leather from cow, sheep and pig leather is no easy matter, making it possible for unscrupulous manufacturers to pass off leather from dogs as leather from legal animals. A report by the Congressional Research Service shows that in 2014, the US imported $8.5bn in leather articles from China. It is unknown how much of each year’s total might be dog or cat leather.

The controversy over dog leather reached new heights in 2014 when an undercover investigator working for People for the Ethical Treatment of Animals (Peta) Asia discovered that dogs were being killed for leather production in China. According to Peta, which is calling on American consumers to forgo all leather goods in favor of vegan substitutes, employees at the facility said that 100-200 dogs were killed there a day and confirmed that the resulting leather was intended for export to and sale in the US market. The investigation shone a light on the underreported underbelly of the animal industry in China, which currently has no comprehensive animal welfare law.

“The dog leather investigation we did, groups that are in the country with us really had no idea,” said Jason Baker, Peta Asia’s vice-president of international operations. “While [the investigations] shock people internationally, they also shock people in China.”

Peta’s footage of the dog slaughterhouse spurred congressional interest. In December 2015, Democratic congressman Alcee Hastings joined colleagues Dina Titus and Steve Cohen in sending a letter to the Customs and Border Protection (CBP) commissioner, R Gil Kerlikowske, calling for better regulation of leather importation to combat the use of dog leather.

“In American culture, dogs are cherished pets and are considered a member of the family,” the letter states. “Accordingly, Americans would not want to hold their four-legged companion’s leash with a dog-skin glove.”

Hastings, Titus and Cohen all have strong track records when it comes to animal welfare issues, and Titus and Hastings, in interviews, both separately described the footage as “disturbing”; the graphic undercover footage taken by the Peta Asia investigator showed dogs being bludgeoned before having their throats cut and their skin removed, sometimes, seemingly, while still alive.

Despite the horrors of Peta’s investigation, Peter Li, associate professor of east Asian politics at University of Houston-Downtown and a China policy specialist and consultant for Humane Society International, says dog fur facilities are few and far between in China. Li said that the dog leather trade is dependent on the dog meat trade; since killing dogs for meat is not illegal in China, the byproducts, including skin and fur, may be used for other purposes.

“Dog leather or dog fur use in garments or other products are not that common in China. While there are a few sweatshops producing dog furs in different places, dog fur is largely a byproduct of dog meat trade,” Li said in an email. “When China outlaws dog eating and the dog meat trade, dog leather as a product shall be gone.”

The dog meat trade has become a focal point in the conversation around Chinese animal welfare, with local animal activists organizing to rescue hundreds of dogs bound for the meat market and protesting against dog consumption; Peta Asia has also focused its efforts on promoting veganism and vegetarianism in the country, and the consumption of dog meat is believed to be declining as pet ownership booms.

Though China, which is the world’s largest leather and fur producer, exporter and consumer, lacks anti-animal abuse legislation, the animal welfare movement has been growing: China ended mandatory animal testing of domestic cosmetics in 2014, local groups have worked to enforce spay and neuter programs, and Bloomberg News reported that in 2014 there were more than 100 animal welfare groups active in the country. Baker, of Peta, said that China was “where Peta is shining the most, but it’s also where the movement as a whole is shining”.

“China seems to be the center of animal protection movement in East Asia … The momentum in China is more robust than in Korea and Japan,” Li said. But he added that government resistance to animal welfare legislation in China remains, due to economic concerns. “The concern of the Chinese government is that such a law could force a lot of the Chinese firms out of business,” he said. “The Chinese authorities remain obsessed with GDP growth and employment.”

While the dog meat and leather trades persist for now, the US’s new interest in preventing the importation of dog leather could help curtail its production, and the terms of the new Trans-Pacific Partnership (TPP) trade deal, of which China is not a member nation, may also have an impact. Although TPP is expected to provide “significant new access” to certain leather markets, it also includes an environment chapter which, though criticized by some for not doing enough to protect farm and livestock animals, nevertheless represents a significant step forward for animal protection and sustainability.

“I believe China would listen to concerns over dog leather export if the issue was raised by foreign governments including the US,” Li said. “Animal welfare consideration in TPP should alert the mainland Chinese authorities that how we treat animals is as much as an international trade issue as a domestic issue. This will force the Chinese authorities to give up the old thinking that ‘animal welfare is used as a trade tool against Chinese exports’.”

Likewise, Titus, who worked on last year’s US congressional letter, believes that public advocacy in the US could be a powerful tool to help end the practice of the dog leather trade.

“Pets are a part of people’s lives here and animal protection is something that’s a very emotional and serious issue. I think it should be an issue for animal lovers to kind of put pressure on the Customs [and Border Protection] commissioner [R Gil Kerlikowske] to be sure that they do everything they can to prevent this from happening, and I think there would be a public uproar about it,” Titus said. “It is possible [that Americans are inadvertently using dog leather], and I think they’d be horrified.”